Spinal Stiffness Research Articles

A new and spontaneous animal model for ankylosing spondylitis is found in cynomolgus monkeys

BackgroundAnkylosing spondylitis is a progressive, disabling joint disease that affects millions worldwide. Given its unclear etiology, studies of ankylosing spondylitis relied heavily on drug-induced or transgenic rodent models which retain only partial clinical features. There is obviously a lack of a useful disease model to conduct comprehensive mechanistic studies.MethodsWe followed a group of cynomolgus monkeys having joint lesions reported of spinal stiffness for 2 years by conducting hematological testing, radiographic examination, family aggregation analysis, pathological analysis, and genetic testing.ResultsThe results confirmed that these diseased animals suffered from spontaneous ankylosing spondylitis with clinical features recapitulating human ankylosing spondylitis disease progression, manifested by pathological changes and biochemical indicators similar to that of ankylosing spondylitis patients.ConclusionThe study offers a promising non-human primate model for spontaneous ankylosing spondylitis which may serve as an excellent substitute for its pre-clinical research.

Neuromechanical Responses to Spinal Manipulation and Mobilization: A Crossover Randomized Clinical Trial

ObjectiveThe purpose of this study was to compare the immediate effect of spinal manipulation (SMa) and spinal mobilization (SMo) on muscular responses, spinal stiffness, and segmental spinal pressure evoked pain in a population of participants with chronic middle back pain (MBP). MethodsIn a crossover randomized trial, 2 experienced chiropractors assessed whether volunteers were eligible for the protocol according to a list of specific inclusion and exclusion criteria. Individuals with MBP participated in 2 experimental sessions within 72 hours. During the first session, participants randomly received a SMa or SMo delivered by an apparatus using a servolinear motor. During the second session, the other modality was delivered. Spinal stiffness and pressure-provoked pain intensity outcomes were assessed before and after each therapy, and muscular responses were recorded during the treatment using surface electromyographic sensors. Signed-rank Wilcoxon tests for muscular responses and generalized model for repeated measure for spinal stiffness and pressure-provoked pain were used for statistical analyses. ResultsAmong the 32 potential participants, 26 (mean age 29.9 [±9.14], 15 women) completed both sessions. Between-group differences were observed for the muscular response amplitude (P < .001), and indeed the normalized RMS muscular response was found to be higher during SMa than SMo. Similar results were observed for pressure-provoked pain intensity at the level of therapeutic modality application (P = .002) as a higher decrease in pain was found after SMa (47.9 [±22.8] to 36.6 [±23.7]) compared with SMo (47.2 [±23.2] to 45.5 [±24.3]). No between-group differences were found for spinal stiffness change, nor for terminal (P = .08) and global spinal stiffness (P = .06). ConclusionIn a controlled environment, spinal manipulation and mobilization generated different muscle responses and had different immediate effects on pressure-provoked pain intensity for participants with MBP.

Conservative Treatment of Low Back Pain with Incidental Finding of Diffuse Idiopathic Skeletal Hyperostosis: A Case Report

Low back pain affects 630 million people worldwide and may result in a physical, social, or psychological liability to those people [1]. Patients with lower back pain commonly will have a higher incidence of functional disability, psychosocial issues, and decreased work productivity [1]. The clinician muscle must provide the correct course of treatment for the patient, clinician [2]. Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory condition resulting from a pathologic calcification and ossification of areas of the spine and possibly other joints [3]. Several risk factors in developing DISH are advanced age, hypertension, diabetes, obesity, and genetics [4,5]. Individuals with DISH are typically asymptomatic; however, a study of two hundred individuals diagnosed with DISH demonstrated that 72% were experiencing back pain and 84% reported overall spinal stiffness [3,4]. Diffuse idiopathic skeletal hyperostosis is an incidental finding in imaging in which the pathogenesis is currently not known [3,4]. To diagnose DISH in the spine it is required to observe at least three bony bridges at the anterolateral spine [4]. The bony bridges are viewed as osteophytes on the anterior portion of the spine [3]. DISH in the cervical spine may lead to symptoms such as dysphagia or upper airway obstruction [3]. Additionally, in the spine DISH has been linked to compression of neural structures resulting in myeloradiculopathy [3]. Structurally, this can lead to spinal stenosis, and spinal cord or nerve root compression [3].Currently, there is one published article describing chiropractic treatment of DISH with flexion distraction technique [6]. Al-Herz et al. [7] discussed exercise therapy for patients with DISH. Additionally, Le et al. [3] discussed, briefly, several strategies for the management of DISH. Current literature does not combine instrument-assisted manipulation, soft tissue therapy, and exercise therapy for the management of DISH. Therefore the purpose of this article is to demonstrate the effectiveness of exercise and manual therapy for the treatment of DISH related pain and dysfunction.

Effect of core strengthening with inspiratory muscle training versus core strengthening on pain, strength and range of motion in chronic low back pain individuals: A randomized control trial

Topic: &ldquo;Effect of core strengthening with inspiratory muscle training versus core strengthening on pain, strength and range of motion in chronic low back pain individuals: A Randomized Control Trial.&rdquo; Background: Low back pain is one of the most common health problems among all the population of the world. Men and women are equally reported to be affected by this condition. 50% of adults and 30% of adolescents are affected at least once. Low back pain often involves altered muscle length relationships, postural changes, Muscular imbalances, variations in location of the centers of mass and of pressure. It has been suggested that the diaphragm plays a role in contributing to spinal stiffness via its influence on intra-abdominal pressure, as well as via direct mechanical effect via the attachments of the diaphragm crurae. The diaphragm, a component of core Stability, plays a role in respiration and trunk stability by controlling intra-abdominal pressure and reducing the stress on the spine through cooperative action with the abdominal and pelvic floor muscles. Objectives: To compare the effect of core strengthening with inspiratory muscle training versus core strengthening on pain, strength and range of motion in chronic low back pain individuals at the end of 6 weeks. Methodology: Ethical committee clearance was taken for the study A written consent was taken from every subject and the entire procedure was explained to the patient in a language understood by the patient. The subjects were divided into two groups by randomization: Group A (n=31) and Group B (n=31) Group A was to continue with the inspiratory muscle training exercises with core strengthening exercises and Group B received the core strengthening exercises for three times a week Single - blinding was maintained throughout the process by blinding the subject to the treatment Numerical Pain Rating Scale, Pressure Biofeedback and Modified Schobar&#39;s test were conducted pre and post intervention. Result: Total 62 male and female of age group 18-35 years, with chronic low back pian volunteered to participate in the study, after 7 dropouts due to various reasons, 30 males (54.5%) and 25 females (45.5%) have completed the 6 weeks of protocol. There was statistically significant difference in NPRS, Pressure Biofeedback values and Modified Schober&rsquo;s Test scores in both the groups. Conclusion: In the present study core strengthening with inspiratory muscle training and core strengthening both were effective in reducing pain and improving strength and range of motion after completing the treatment protocols. But the improvement in extension range of motion is more in core strengthening group when compared with core strengthening with inspiratory muscle training group.

Influence of Axial Load and a 45-Degree Flexion Head Position on Cervical Spinal Stiffness in Healthy Young Adults

Background: Neck pain is a major cause of disability worldwide. Poor neck posture such as using a smartphone or work-related additional cervical axial load, such headgear of aviators, can cause neck pain. This study aimed at investigating the role of head posture or additional axial load on spinal stiffness, a proxy measure to assess cervical motor control.Methods: The posterior-to-anterior cervical spinal stiffness of 49 young healthy male military employees [mean (SD) age 20 ± 1 years] was measured in two head positions: neutral and 45-degree flexed head position and two loading conditions: with and without additional 3 kg axial load. Each test condition comprised three trials. Measurements were taken at three cervical locations, i.e., spinous processes C2 and C7 and mid-cervical (MC).Results: Cervical spinal stiffness measurements showed good reliability in all test conditions. There was a significant three-way interaction between location × head position × load [F(2, 576) = 9.305, p < 0.001]. Significant two-way interactions were found between measurement locations × loading [F(2, 576) = 15.688, p < 0.001] and measurement locations × head position [F(2, 576) = 9.263, p < 0.001]. There was no significant interaction between loading × head position [F(1, 576) = 0.692, p = 0.406]. Post hoc analysis showed reduction of stiffness in all three measurement locations in flexion position. There was a decrease in stiffness in C2 with loading, increase in stiffness in C7 and no change in MC.Discussion: A flexed head posture leading to decreased stiffness of the cervical spine might contribute to neck pain, especially if the posture is prolonged and static, such as is the case with smartphone users. Regarding the additional load, stiffness decreased high cervical and increased low cervical. There was no change mid cervical. The lower spinal stiffness at the high cervical spine might be caused by capsular ligament laxity due to the buckling effect. At the lower cervical spine, the buckling effect seems to be less dominant, because the proximity to the ribs and sternum provide additional stiffness.

Total hip arthroplasty in fused hips with spine stiffness in ankylosing spondylitis.

Ankylosing spondylitis (AS) is characterized by involvement of the spine and hip joints with progressive stiffness and loss of function. Functional impairment is significant, with spine and hip involvement, and is predominantly seen in the younger age group. Total hip arthroplasty (THA) for fused hips with stiff spines in AS results in considerable improvement of mobility and function. Spine stiffness associated with AS needs evaluation before THA. Preoperative assessment with lateral spine radiographs shows loss of lumbar lordosis. Spinopelvic mobility is reduced with change in sacral slope from sitting to standing less than 10 degrees conforming to the stiff pattern. Care should be taken to reduce acetabular component anteversion at THA in these fused hips, as the posterior pelvic tilt would increase the risk of posterior impingement and anterior dislocation. Fused hips require femoral neck osteotomy, true acetabular floor identification and restoration of the hip center with horizontal and vertical offset to achieve a good functional outcome. Cementless and cemented fixation have shown comparable long-term results with the choice dependent on bone stock at THA. Risks at THA in AS include intraoperative fractures, dislocation, heterotopic ossification, among others. There is significant improvement of functional scores and quality of life following THA in these deserving young individuals with fused hips and spine stiffness.

Understanding the Disease Burden of Unemployed Patients With Axial Spondyloarthritis: Results From the Spanish Atlas 2017.

To evaluate differences in sociodemographic factors and patient-reported outcomes (PROs) between unemployed and employed patients with axial spondyloarthritis (axSpA), and to explore work-related issues (WRIs). Data from an online survey of 680 unselected patients of the Atlas of Axial Spondyloarthritis in Spain 2017 were analyzed. Active workforce participants were divided into employed and unemployed groups according to International Labour Organization definitions. Sociodemographic characteristics, PROs (Bath Ankylosing Spondylitis Disease Activity Index [0-10], Spinal Stiffness Index [3-12], Functional Limitation Index [0-54], and psychological distress through the 12-item General Health Questionnaire [0-12]) were assessed. Logistic regression analysis was used to evaluate the association with unemployment status. Four hundred fifteen (63.6%) patients with axSpA were categorized in the active population, of which 325 (78.3%) were employed and 90 (21.7%) unemployed. Of the unemployed patients, 62.8% (n = 54) declared that their joblessness was due to axSpA. Of the employed patients, 170 (54.3%) reported WRIs in the year prior to the survey, the most frequent being difficulty fulfilling working hours (44.1%), missing work for doctor appointments (42.9%), and taking sick leave (37.1%). Being unemployed was associated with lower educational level (OR = 2.92), disease activity (OR = 1.37), spinal stiffness (OR = 1.21), functional limitation (OR = 1.05), worse mental health (OR = 1.15), anxiety (OR = 2.02), and depression (OR = 2.69) in the univariable models; and with lower educational level (OR = 2.76) and worse mental health (OR = 1.15) in the multivariable analysis. Results show significant differences between employed and unemployed patients with axSpA. Employed patients with axSpA endure many problems at work related to their condition, whereas unemployed patients present worse disease outcomes associated with greater psychological distress.

240. Epidural Involvement Complicating Pyogenic Spondylodiscitis

BackgroundPyogenic spondylodiscitis is an infection of the intervertebral disc(s) and/or adjacent vertebrae. It might be associated with epidural involvement. We aimed to study clinical, laboratory and evolutionary features of epidural involvement complicating pyogenic spondylodiscitis.MethodsWe conducted a retrospective study including patients hospitalized for spondylodiscitis with epidural involvement in the infectious diseases department between 2007 and 2019.ResultsWe included 22 patients among whom 16 were males (72.7%). The mean age was 64±11 years. Eleven patients had diabetes mellitus (50%). The onset of the disease was acute in 18 cases (81.8%) and sub-acute in 4 cases (18.2%). The median delay to diagnosis was 4 [2-13] weeks. The revealing symptoms were back pain (95.5%), fever (68.2%) and asthenia (54.5%). Motor deficit was noted in 9 cases (40.9%), sensory deficit in 4 cases (18.2%) and sphincter dysfunction in one case (4.5%). Physical examination revealed spinal tenderness (77.3%), paravertebral tenderness (22.7%) and spinal stiffness (18.2%). Blood cultures were positive in 13 cases (59.1%) represented by Staphylococcus aureus (31.8%). Elevated C-reactive protein levels (81.8%) and accelerated erythrocyte sedimentation rate (63.6%) were noted. Imaging features showed vertebral body osteolysis (81.8%), inflammation of adjacent soft tissue (81.8%), spinal cord compression (40.9%) and psoas abscess (13.6%). Along with medical treatment, immobilisation (72.7%), abscess drainage (13.6%) and surgery (9.1%) were indicated. The disease evolution was favourable in 20 cases (90.9%). Two patients were dead (9.1%). Sequelae were noted in 9 cases (40.9%) represented by back pain (31.8%) and spinal deformity (9.1%).ConclusionSpondylodiscitis complicated with epidural involvement might lead to complications and sequelae if not promptly diagnosed and treated. Disclosures All Authors: No reported disclosures

Impact of Variations in Water Concentration on the Nanomechanical Behavior of Type I Collagen Microfibrils in Annulus Fibrosus.

Radial variation in water concentration from outer to inner lamellae is one of the characteristic features of annulus fibrosus (AF). In addition, water concentration changes are also associated with intervertebral disc (IVD) degeneration. Such changes alter the chemo-mechanical interactions among the biomolecular constituents at molecular level, affecting the load-bearing nature of IVD. This study investigates mechanistic impacts of water concentration on the collagen type I microfibrils in AF using molecular dynamics simulations. Results show, in axial tension, that increase in water concentration (WC) from 0% to 50% increases the elastic modulus from 2.7 GPa to 3.9 GPa. This is attributed to combination of shift in deformation from backbone straightening to combined backbone stretching- intermolecular sliding and subsequent strengthening of tropocollagen-water (TC-water-TC) interfaces through water bridges and intermolecular electrostatic attractions. Further increase in WC to 75% reduces the modulus to 1.8 GPa due to shift in deformation to polypeptide straightening and weakening of TC-water-TC interface due to reduced electrostatic attraction and increase in the number of water molecules in a water bridge. During axial compression, increase in WC to 50% results in increase in modulus from 0.8 GPa to 4.5 GPa. This is attributed to the combination of the development of hydrostatic pressure and strengthening of the TC-water-TC interface. Further increase in WC to 75% shifts load-bearing characteristic from collagen to water, resulting in a decrease in elastic modulus to 2.8 GPa. Such water-mediated alteration in load-bearing properties acts as foundations toward AF mechanics and provides insights toward understanding degeneration-mediated altered spinal stiffness.

Mechanical defensive adaptations of three Mediterranean sea urchin species.

In the Mediterranean, Paracentrotus lividus and Sphaerechinus granularis are important drivers of benthic ecosystems, often coexisting in sublittoral communities. However, the introduction of the invasive diadematoid Diadema setosum, which utilizes venomous spines, may affect these communities. To describe the mechanical properties of the test and spines of these three species, specimens were collected in winter of 2019 from the sublittoral zone of the Dodecanese island complex, southeastern Aegean Sea. This region serves as a gateway for invasive species to the Mediterranean Sea. Crushing test was conducted on live individuals, while 3‐point bending test was used to estimate spine stiffness. Porosity and mineralogy of the test and spine, thickness of the test, and breaking length of the spine were measured and compared, while the microstructural architecture was also determined. The test of S. granularis was the most robust (194.35 ± 59.59 N), while the spines of D. setosum (4.76 ± 2.13 GPa) exhibited highest flexibility. Increased porosity and thickness of the test were related to increased robustness, whereas increased flexibility of the spine was attributed to high porosity, indicating that porosity in the skeleton plays a key role in preventing fracture. The spines of S. granularis exhibited highest length after fracture % (71.54 ± 5.5%). D. setosum exhibited higher values of Mg concentration in the test (10%) compared with the spines (4%). For the first time, the mineralogy of an invasive species is compared with its native counterpart, while a comparison of the mechanical properties of different species of the same ecosystem also takes place. This study highlights different ways, in which sea urchins utilize their skeleton and showcases the ecological significance of these adaptations, one of which is the different ways of utilization of the skeleton for defensive purposes, while the other is the ability of D. setosum to decrease the Mg % of its skeleton degrading its mechanical properties, without compromising its defense, by depending on venomous bearing spines. This enables this species to occupy not only tropical habitats, where it is indigenous, but also temperate like the eastern Mediterranean, which it has recently invaded.

Simultaneously varying back stiffness and trunk compression in a passive trunk exoskeleton during different activities: A pilot study.

Passive trunk exoskeletons support the human body with mechanical elements like springs and trunk compression, allowing them to guide motion and relieve the load on the spine. However, to provide appropriate support, elements of the exoskeleton (e.g., degree of compression) should be intelligently adapted to the current task. As it is not currently clear how adjusting different exoskeleton elements affects the wearer, this study preliminarily examines the effects of simultaneously adjusting both exoskeletal spinal column stiffness and trunk compression in a passive trunk exoskeleton. Six participants performed four dynamic tasks (walking, sit-to-stand, lifting a 20-lb box, lifting a 40-lb box) and experienced unexpected perturbations both without the exoskeleton and in six exoskeleton configurations corresponding to two compression levels and three stiffness levels. While results are preliminary due to the small sample size and relatively small increases in stiffness, they indicate that both compression and stiffness may affect kinematics and electromyography, that the effects may differ between activities, and that there may be interaction effects between stiffness and compression. As the next step, we will conduct a larger study with the same protocol more participants and larger stiffness increases to systematically evaluate the effects of different exoskeleton characteristics on the wearer.Clinical Relevance- Trunk exoskeletons can support wearers during a variety of different tasks, but their configuration may need to be intelligently adjusted to provide appropriate support. This pilot study provides information about the effects of exoskeleton back stiffness and trunk compression on the wearer, which can be used as a basis for more effective device design and usage.

Anteroposterior shear stiffness of the upper thoracic spine at quasi-static and dynamic loading rates-Anin vitro biomechanical study.

To evaluate the biomechanical properties of the upper thoracic spine in anterior-posterior shear loading at various displacement rates. Thesedata broadenour understanding of thoracic spine biomechanics and inform efforts to model the spine and spinal cord injuries. Seven T1-T2 thoracic functional spinal units were loaded non-destructively by a pure shear force up to 200 N, starting from a neutral posture. Tests were run in both posterior and anterior directions, at displacement rates of 1, 10, and 100 mm/s. The three-dimensional motion of the specimen was recorded at 1000 Hz. Individual and averaged load-displacement curves were generated and specimen stiffnesses were calculated. Due to a nonlinear response of the specimens, stiffness was defined separately for both the lower half and the upper half of the specimen range of motion. Specimens were significantly stiffer in the anterior direction than in the posterior direction, across all rates. At low displacements, the anterior stiffness averaged 230 N/mm, 76% higher than the low displacement posterior stiffness of 131 N/mm. At high displacements, anterior stiffness averaged 258 N/mm, 51% stiffer than the high displacement posterior stiffness of 171 N/mm. Shear displacement rate had a small effect on the load response, with the 100 mm/s rate causing a mildly stiffer response at low displacements in the anterior direction. Overall, the load-displacement response exhibited pseudo-quadratic behavior at 1 and 10 mm/s but became more linear at 100 mm/s. The shear stiffness in the upper thoracic spine is greatest in the anterior loading direction, being 51%-76% greater than posterior, most likely due to facet interactions. The effect of the shear displacement rate is low.

Spinal pathology and outcome post-THA: does segment of arthrodesis matter?

The presence of lumbar spine arthrodesis (SA) is associated with abnormal spinopelvic characteristics and inferior outcome post total hip arthroplasty (THA). However, whether patients with upper segment SA are also at increased risk of complications is unknown. This study aims to (1) determine if upper segment SA is associated with inferior THA outcomes; (2) assess spino-pelvic characteristics; and (3) test whether static or dynamic spinopelvic characteristics correlate with outcome post-THA. In this retrospective, case-matched, cohort study from a tertiary referral centre, 40 patients (59 hips) that had undergone both THA and any level of spinal arthrodesis (49 THA-Lumb and 10 THA-Cerv) were compared with 41 patients (59 hips) who had THA-only without known spinal pathology. Spino-pelvic characteristics [including severity of Degenerative-Disc-Disease (DDD); spinal balance and stiffness] and outcome, including patient reported outcome measures (PROMs), at minimum of 1-year post-THA were assessed. THA-Lumb and THA-Cerv groups had greater number of complications and inferior hip and spinal PROMs compared to THA-Only (p < 0.001). Similar spinopelvic characteristics were seen between the THA-Cerv and THA-Lumb, which were significantly different to the THA-only group. The presence of DDD and unbalanced or stiff spine was associated with increased dislocation and inferior PROMs in the whole cohort. THA in the presence of SA, regardless of level, is associated with inferior outcomes and an increased risk for dislocation. The presence of a SA is associated with increased risk of adverse spinopelvic characteristics. Such characteristics were strongly associated with increased dislocation-risk and inferior PROMs. It is likely that these adverse characteristics are the most important adverse predictor, rather than segment of SA per se.

Ixekizumab improves spinal pain, function, fatigue, stiffness, and sleep in radiographic axial Spondyloarthritis: COAST-V/W 52-week results

BackgroundThis analysis assessed improvements in patients with radiographic axial spondyloarthritis (r-axSpA) treated with ixekizumab in the Assessment of Spondyloarthritis International Society (ASAS) treatment response domains and additional patient-reported outcomes at 1 year of treatment.MethodsCOAST-V and COAST-W were 52-week, phase 3, randomized controlled trials evaluating the efficacy and safety of ixekizumab in biologic disease-modifying antirheumatic drug (bDMARD)-naïve and tumor necrosis factor inhibitor (TNFi)-experienced patients with radiographic spondyloarthritis, respectively. Patients were treated with 80-mg ixekizumab either every 2 weeks or every 4 weeks. Patient-reported outcomes included Patient Global Disease Activity, Spinal Pain, stiffness as measured by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) Questions 5 and 6, function as measured by the Bath Ankylosing Spondylitis Functional Index, fatigue as measured by the Fatigue Numeric Rating Scale and BASDAI question 1, Spinal Pain at Night, and sleep quality as measured by the Jenkins Sleep Evaluation Questionnaire. Mixed-effects models for repeated measures were used to analyze changes from baseline in patient-reported outcomes from weeks 1 to 16, and descriptive statistics were reported from weeks 20 to 52. Analysis of covariance with Scheffé’s method was used for the ASAS response association analyses.ResultsThis study assessed 341 bDMARD-naïve and 316 TNFi-experienced patients in the placebo-controlled blinded treatment dosing period (weeks 1–16) as well as 329 bDMARD-naïve and 281 TNFi-experienced patients in the dose double-blind extended treatment period (weeks 20–52). bDMARD-naïve or TNFi-experienced patients treated with ixekizumab every 2 weeks and every 4 weeks reported improvements in patient global disease activity, spinal pain, function, stiffness, fatigue, spinal pain at night, and sleep quality through week 52. Greater correlations with improvements in all response domains were seen when comparing ASAS40 responders to ASAS20 non-responders (p < 0.001), with up to 10.5-fold greater improvements observed in ASAS40 responses compared with ASAS20 non-responders. Function and fatigue demonstrated the highest values.ConclusionsIxekizumab-treated bDMARD-naïve and TNFi-experienced patients with radiographic axial spondyloarthritis achieving ASAS40 reported sustained and consistent improvement in all ASAS response domains and other patient-reported outcomes though week 52, with spinal pain, function, and stiffness as major drivers of the response.Trial registrationNCT02696785 and NCT02696798, March 2, 2016.

CORR Insights®: A Modeling Study of a Patient-specific Safe Zone for THA: Calculation, Validation, and Key Factors Based on Standing and Sitting Sagittal Pelvic Tilt.

CORR Insights®: A Modeling Study of a Patient-specific Safe Zone for THA: Calculation, Validation, and Key Factors Based on Standing and Sitting Sagittal Pelvic Tilt.

A cross-sectional analysis of persistent low back pain, using correlations between lumbar stiffness, pressure pain threshold, and heat pain threshold

IntroductionLittle is known about the underlying biomechanical cause of low back pain (LBP). Recently, technological advances have made it possible to quantify biomechanical and neurophysiological measurements, potentially relevant factors in understanding LBP etiology. However, few studies have explored the relation between these factors. This study aims to quantify the correlation between biomechanical and neurophysiological outcomes in non-specific LBP and examine whether these correlations differ when considered regionally vs. segmentally.MethodsThis is a secondary cross-sectional analysis of 132 participants with persistent non-specific LBP. Biomechanical data included spinal stiffness (global stiffness) measured by a rolling indenter. Neurophysiological data included pain sensitivity (pressure pain threshold and heat pain threshold) measured by a pressure algometer and a thermode. Correlations were tested using Pearson’s product-moment correlation or Spearman’s rank correlation as appropriate. The association between these outcomes and the segmental level was tested using ANOVA with post-hoc Tukey corrected comparisons.ResultsA moderate positive correlation was found between spinal stiffness and pressure pain threshold, i.e., high degrees of stiffness were associated with high pressure pain thresholds. The correlation between spinal stiffness and heat pain threshold was poor and not statistically significant. Aside from a statistically significant minor association between the lower and the upper lumbar segments and stiffness, no other segmental relation was shown.ConclusionsThe moderate correlation between spinal stiffness and mechanical pain sensitivity was the opposite of expected, meaning higher degrees of stiffness was associated with higher pressure pain thresholds. No clinically relevant segmental association existed.

Physical activity in patients with axial spondyloarthritis in a multi-ethnic south-east Asian country

BackgroundPatients with axial spondyloarthritis (axSpA) may experience spinal stiffness and pain, leading to reduced physical function and quality of life. Despite the benefits of physical activity (PA) and exercise, previous studies have demonstrated lower levels of PA among patients with axSpA. This study aims to examine the patterns of PA among patients with axSpA compared to the general population in a multi-ethnic Asian country.MethodsThis was a cross-sectional study conducted between May 2016 and Jan 2017. Consecutive patients with axSpA were recruited at an outpatient rheumatology clinic at Singapore General Hospital, the largest tertiary hospital in Singapore. Controls were based on a previous cross-sectional study. PA was assessed using the Global Physical Activity Questionnaire (GPAQ).ResultsSeventy-four patients with axSpA were recruited and compared with 2679 controls. Lower proportion of patients with axSpA met the WHO recommendations for PA (axSpA = 77.0%, controls = 89.7%, p < 0.001). More patients with axSpA had high level of sedentary activity compared to controls (axSpA = 56.8%, controls = 36.1%, p < 0.001). Levels of PA did not differ between patients with inactive versus active axSpA disease (p = 0.91).ConclusionsProportion of patients with axSpA meeting the WHO recommendations for PA differed significantly from the general population, and level of PA did not differ between patients with active and inactive axSpA disease. Higher levels of sedentary activity were seen in patient with axSpA compared to the general population, highlighting the need for interventions to promote PA among patients with axSpA.

SPINAL INVOLVEMENT IN PSORIATIC ARTHRITIS, CLINICAL AND RADIOLOGICAL STUDY

Psoriatic arthritis is chronic inflammatory condition affecting multiple tissues including skin and joints. Axial psoriatic arthritis (axPsA) forms part of the SpA spectrum, may occur in the form of spondylitis with or without sacroiliitis. Spondylitis presents clinically with spinal stiffness and pain, while sacroiliitis causes alternating buttock pain. Although different classification criteria have been used for axPsA, a clear distinction is still not available. Spondylitis occurs in 40% of patients with PsA and may result in fusion of the vertebrae. These manifestations may be present on radiological examination without symptoms or signs. Some patients had silent axial disease, thus it was suggested that in order to identify axPsA, recognition of which has prognostic value, rheumatologists should consider conducting axial imaging for all patients with PsA regardless the presence of back pain. Aim of the work: To study spinal involvement in patients with psoriatic arthritis clinically and radiographically.Patients and MethodsPatients:Fifty patients diagnosed with PsA according to the classification criteria for psoriatic arthritis (CASPAR) were enrolled. Patients were classified into three groups based on the absence or presence of spinal involvement clinically and/or radiographically: Group (Ι): patients with peripheral PsA (pPsA) only.Group (ΙI): PsA patients with radiographic axial involvement (AxPsA-R) Group (ΙII): PsA patients with clinical and radiographic axial involvement (AxPsA-CR). Patients with orthopedic diseases or other rheumatic disorders affecting the spine and psychiatric and neurological disorders were excluded.

Biomechanical changes in the lumbar spine following spaceflight and factors associated with postspaceflight disc herniation

For chronic low back pain, the causal mechanisms between pathological features from imaging and patient symptoms are unclear. For instance, disc herniations can often be present without symptoms. There remains a need for improved knowledge of the pathophysiological mechanisms that explore spinal tissue damage and clinical manifestations of pain and disability. Spaceflight and astronaut health provides a rare opportunity to study potential low back pain mechanisms longitudinally. Spaceflight disrupts diurnal loading on the spine and several lines of evidence indicate that astronauts are at a heightened risk for low back pain and disc herniation following spaceflight.To examine the relationship between prolonged exposure to microgravity and the elevated incidence of postflight disc herniation, we conducted a longitudinal study to track the spinal health of twelve NASA astronauts before and after approximately 6 months in space. We hypothesize that the incidence of postflight disc herniation and low back complaints associates with spaceflight-included muscle atrophy and pre-existing spinal pathology.This is a prospective longitudinal study.Our sample included a cohort of twelve astronaut crewmembers.From 3T MRI, we quantified disc water content (ms), disc degeneration (Pfirrmann grade), vertebral endplate irregularities, facet arthropathy and/ fluid, high intensity zones, disc herniation, multifidus total cross-sectional area (cm2), multifidus lean muscle cross-sectional area (cm2), and muscle quality/composition (%). From quantitative fluoroscopy we quantified, maximum flexion-extension ROM (°), maximum lateral bending ROM (°), and maximum translation (%). Lastly, patient outcomes and clinical notes were used for identifying postflight symptoms associated with disc herniations from 3T MRI.Advanced imaging data from 3T MRI were collected at three separate time points in relation to spending six months in space: (1) within a year before launch ("pre-flight"), (2) within a week after return to Earth ("post-flight"), and (3) between 1 and 2 months after return to Earth ("recovery"). Fluoroscopy of segmental kinematics was collected at preflight and postflight timepoints. We assessed the effect of spaceflight and postflight recovery on longitudinal changes in spinal structure and function, as well as differences between crew members who did and did not present a symptomatic disc herniation following spaceflight.Half of our astronauts (n=6) experienced new symptoms associated with a new or previously asymptomatic lumbar disc protrusion or extrusion following spaceflight. We observed decreased multifidus muscle quality following spaceflight in the lower lumbar spine, with a reduced percentage of lean muscle at L4L5 (-6.2%, p=.009) and L5S1 (-7.0%, p=.006) associated with the incidence of new disc herniation. Additionally, we observed reduced lumbar segment flexion-extension ROM for L2L3 (-17.2%, p=.006) and L3L4 (-20.5%, p=.02) following spaceflight, and furthermore that reduced ROM among the upper three lumbar segments (-24.1%, p=.01) associated with the incidence of disc herniation. Existing endplate pathology was most prevalent in the upper lumbar spine and associated with reduced segmental ROM (-20.5%, p=.02).In conclusion from a 10-year study investigating the effects of spaceflight on the lumbar spine and risk for disc herniation, we found the incidence of lumbar disc herniation following spaceflight associates with compromised multifidus muscle quality and spinal segment kinematics, as well as pre-existing spinal endplate irregularities. These findings suggest differential effects of spinal stiffness and muscle loss in the upper versus lower lumbar spine regions that may specifically provoke risk for symptomatic disc herniation in the lower lumbar spine following spaceflight. Results from this study provide a unique longitudinal assessment of mechanisms and possible risk factors for developing disc herniations and related low back pain. Furthermore, these findings will help inform physiologic countermeasures to maintain spinal health in astronauts during long-duration missions in space.

Finite Element Method for the Evaluation of the Human Spine: A Literature Overview.

The finite element method (FEM) represents a computer simulation method, originally used in civil engineering, which dates back to the early 1940s. Applications of FEM have also been used in numerous medical areas and in orthopedic surgery. Computing technology has improved over the years and as a result, more complex problems, such as those involving the spine, can be analyzed. The spine is a complex anatomical structure that maintains the erect posture and supports considerable loads. Applications of FEM in the spine have contributed to the understanding of bone biomechanics, both in healthy and abnormal conditions, such as scoliosis, fractures (trauma), degenerative disc disease and osteoporosis. However, since FEM is only a digital simulation of the real condition, it will never exactly simulate in vivo results. In particular, when it concerns biomechanics, there are many features that are difficult to represent in a FEM. More FEM studies and spine research are required in order to examine interpersonal spine stiffness, young spine biomechanics and model accuracy. In the future, patient-specific models will be used for better patient evaluations as well as for better pre- and inter-operative planning.